Download Enterotube Results

Microbiology Laboratory
Instructor: Elmar Schmid, Ph.D.
________________________
(Student Name)
BBL Enterotube Results Table
Lab Assignments:
1. Incubate the inoculated bacterial sample in the enterotube for 18 – 24 hours at 37oC in an
incubator
2. Record the observed color changes of the medium in the individual reaction chambers of the
BBL enterotubes as positive or negative reaction into the Results Table below
3. Determine the 5-digit code of the bacteria under investigation which is retrieved after
analyzing the color changes and by totaling the number of positive reactions; write this
number into the Enterotube II results pad below
4. Identify your bacterium under investigation with the help of the instructor-supplied tabulated
Computer Coding System and Interpretation Guide (coding manual) and write the name
of the identified bacterium (genus/species) into the Enterotube Results Pad below
Enterotube II Testing System Results Table
Parameter
(Chamber)
1. Glucose
Gas
2. Lysine
DC
3. Ornithine
DC
4. H2S
Indole
Description
detection of acids as end
products of glucose
fermentation; pH change
detection of gas formation
(H2, CO2) due to glucose
fermentation; uplifting of
wax layer
formation of alkaline end
product cadaverine from
lysine due to lysine
decarboxylase activity;
pH change
formation of alkaline end
product putrescine from
ornithine due to ornithine
decarboxylase activity;
pH change
H2S gas & sulfurcontaining compounds
present in the medium,
react with iron salts to form
black-colored ferric sulfate
precipitate;
formation of indole due to
metabolism of tryptophan
by bacterial tryptophanase
enzyme;
color change from
colorless to cherry-red
after addition of Kovacs
reagent (after 24h)
indicates positive reaction
Negative (-)
Reaction
(color)
red
(orange)
Positive (+)
Reaction
(color)
YYeelllloow
w
No uplift of
wax
Wax layer uplifted
yyeelllloow
w
purple
yyeelllloow
w
purple
bbeeiiggee
black
precipitate
color-less
red
(after addition of
Kovacs reagent)
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Your Result
Microbiology Laboratory
Instructor: Elmar Schmid, Ph.D.
5. Adonitol
6. Lactose
7.
Arabinose
8. Sorbitol
9. VogesProskauer
(VP) test
10. Dulcitol
PA test
11. Urease
12. Citrate
detection of acidic end
products after fermentation
of adonitol; pH change
detection of acidic end
products after fermentation
of lactose sugar; pH
change
detection of acidic end
products after fermentation
of the sugar arabinose;
pH change
detection of the acidic end
products after fermentation
of the sugar sorbitol;
change in color of pH
indicator dye in medium
detection of the
intermediate product
acetoin appearing during
glucose fermentation;
addition of KOH/creatine
and naphthol solution after
incubation required!
slow formation of red color
if +
detection of acidic end
products after fermentation
of the sugar dulcitol;
change of color of pH
indicator
detects the formation of
pyruvic acid from the
deamination of the amino
acid phenylalanine (PA);
pyruvic acid reacts with
ferric salts to form
black/smoky grey color
detects the hydrolysis of
urea to ammonia in the
presence of urease;
color change of pH
indicator dye
detection of alkaline end
products after utilization of
citrate as carbon source;
color change of pH
indicator dye
red
((oorraannggee))
yyeelllloow
w
red
((oorraannggee))
yyeelllloow
w
red
((oorraannggee))
yyeelllloow
w
red
((oorraannggee))
yyeelllloow
w
ccoolloorrlleessss
rreedd
ggrreeeenn
yyeelllloow
w
ggrreeeenn
bbllaacckk//ggrreeyy
bbeeiiggee
rreedd--ppuurrppllee
ggrreeeenn
bblluuee
Note: If no color change, or an orange color, is observed in the glucose compartment (= chamber 1) of this
testing system, but growth is observable, then the inoculated bacterium is NOT a member of the
Enterobacteriaceae family.
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Microbiology Laboratory
Instructor: Elmar Schmid, Ph.D.
Enterotube II Results Pad
1. Indicate each positive reaction you observed in the enterotube (after 18-24 hours) by circling
the corresponding number below the appropriate compartment (see #) shown on the second
row of the Results Pad below
2. Add the circled numbers for each groups up and write the sum on the corresponding lines
shown below the table
(e.g. if the enterotube showed a + reaction for glucose and gas then you write a number 2 + 1
= “3” on the first line)
3. The established ID code identifies the bacterium under investigation with the help of the
supplied Interpretation Guide (= Coding Manual)
For example: the ID Code 3 4 3 6 3
the ID code 2 0 7 7 3
#1
Glucose Gas
2
1
codes for
codes for
Klebsiella pneumoniae
Klebsiella oxytoca
#2
#3
#4
#5
#6
#7
#8
#9
#10
#11
#12
LYS
ORN
H2S Indole
Ado
Lac
Ara
Sorb
VP
Dulc PA
Urea
Citrate
4
2
2
1
4
2
+/-
1
4
1
4
2
1
Totaled ID Code
______
___________
____________
____________________
_________
Name of identified bacterium
________________________________________________________________
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